The invention relates to an air routing system, particularly an intake system of an internal combustion engine. The invention further relates to an intake module, particularly an intake module of an internal combustion engine.
Air routing systems for use as an intake tract for internal combustion engines are known, for example, from EP 0664390. This document notably describes the integration of the air filter housing and the intake pipe in a single cast part. Further components, such as an air/oil separator for the crankcase gases, may also be integrated into the intake module thus created. These measures are also particularly suitable for the design of plastic intake pipes produced by means of multishell technology.
The increasing requirements for engine output and driving comfort, however, result in increasingly tighter space conditions in the engine compartment, e.g., due to the increasing number of engine components. Consequently, the air intake system for the engine must also have a more compact design. On the other hand, certain minimum volumes are required to produce the necessary acoustic properties of the intake system.
Known technical solutions suggest approaches to component integration in view of the reduced overall space. But these can be further improved.
The object of the invention is to provide an air intake system, particularly for internal combustion engines, which optimally uses the available space and thereby creates additional volumes that can serve to enhance the behavior of the intake system with respect to its flow characteristics and its acoustics. This object is attained by the present invention as described hereinafter.
The air routing system according to the invention is provided particularly for engines that are charged by compressors and have an air bypass to compensate the compressor overpressure in the high-speed range of the engine. This bypass line supplies the excess combustion air back to the filtered air pipe behind the air filter in front of the compressor. According to the invention, said bypass line is integrated into the lower shell of the intake module. In contrast to a hose assembly with round cross section, which might alternatively be considered, this solution does not create a dead space. Thus, the available clearance is optimally utilized. Furthermore, this measure clearly reduces the complexity of the final assembly of the vehicle since replacing the hose with the integrated channel eliminates a component that is difficult to handle. An additional advantage is a reduction of the total weight of the intake system.
A special embodiment of the bypass line provides that it be arranged around the intake air plenum. This achieves not only a component integration but also a functional integration. The volume of the bypass line in this embodiment additionally acts as sound insulation.
A further modification of the bypass line provides that the connection of the bypass line to the compressor be made of an elastic molded part.
This part can be optimally adapted to the available clearance and thus facilitates assembly.
A further embodiment of the invention provides for a resonant cavity in the intermediate line between filter and compressor into which the bypass line simultaneously opens. This, too, is a functional integration measure. The air supply line may simultaneously be used to optimize the intake housing acoustically.
Another approach according to the invention for optimizing the space of the air intake system provides for a hood on the air filter housing, which together with the intake pipe forms the core part of the intake module. This hood should be capable of being mounted quickly, which is advantageously ensured by a snap on connection. The mounted hood uses a clearance that must be provided for the assembly tools of the intake pipe or other components in the engine compartment. Assembly of the intake pipe or the other engine components is thus affected with the hood removed, which can subsequently be mounted again.
According to one embodiment of the inventive concept of the filter housing with hood, the air volume available within the filter housing is enlarged. This has a positive effect on the noise at the mouth of the intake pipe, since the additional volume acts as a damper. Furthermore, the distribution of the air over the filter element is improved. This increases the filter""s service life.
According to a further embodiment of the invention the unfiltered-air-side inlet of the filter housing is provided within the hood. This measure makes it possible to combine the hood with the air intake of the intake system into a preassembled unit. In this way it is possible to further optimize the assembly of the engine.
These and other features of preferred further embodiments of the invention are set forth in the claims as well as in the description and the drawings. The individual features may be implemented either alone or in combination in the embodiment of the invention or in other fields of application and may represent advantageous embodiments that are protectable per se, for which protection is hereby claimed.